Research on self-excited initiation of a Medium-voltage DC (MVDC) multiphase synchronous generator-rectifier system

This paper has described the excitation system of a Medium-voltage DC (MVDC) multiphase synchronous generator-rectifier system and calculated the minimum frequency of the pilot-exciter needed for self-excited initiation. On this basis, a double closed-loop V/F control method is proposed according to the classical PI control algorithm for self-excited initiation. With the method, a prototype is constructed for test. The results show that both the self-excitation initiating and the speed-rising processes of the generator set have changed synchronously thus to reduce the time needed for MVDC multiphase synchronous generator-rectifier system to start and finish establishing the nominal DC voltage.